The invention relates to a linear guide unit that has a guide rail extending in a longitudinal direction, and a guide carriage that is guided on the guide rail in the longitudinal direction; the guide rail has at least one running rail, which is equipped with at least two races that have different load transmission directions and are separated from each other by a load-free surface segment.
A linear guide unit of this kind is known, for example, from U.S. Pat. No. 5,800,065. In the linear guide unit disclosed therein, the running rails are positioned in lateral recesses of the guide rail that have been previously cut into the guide rail by means of cutting machining, e.g. milling, in order to be able to assure the required degree of precision fit. This cutting machining increases the complexity of manufacturing the linear guide unit and consequently increases the manufacturing costs of the linear guide unit significantly. Although only the balls of a single recirculating ball element travel in the running rail, the running rail has two races with different load transmission directions. The roller elements contact the running rail in two different regions of the running rail that are separated from each other by a load-free surface segment. Together with a correspondingly embodied running rail contained in the guide carriage, this consequently produces a so-called four-point contact of the balls.
Reference is also made to U.S. Pat. No. 5,217,308, DE 100 03 619 A1, and U.S. Pat. No. 1,500,166.
EP 0 213 160 A1 and DE 44 28 558 A1 have essentially disclosed attaching a running rail to a guide rail by means of roller insertion. To this end, a surface section of the guide rail associated with the running rail is provided with a plurality of supporting ribs, which are deformed during the roller insertion and thus permit a precise relative positioning of the running rail and guide rail. The advancing direction of the roller insertion tool extends essentially in the protrusion direction of the supporting ribs, which in turn protrude essentially in the operating load transmission direction. This makes it possible to prevent the supporting ribs from bending away laterally during the roller insertion.